Brainstem Flashcards
Radicular arteries feed into
the spinal arteries
Cerebellar peduncles are on _____ and are not seen ____
each side of midline, not seen in sagittal (midline) sections
Cerebellar peduncles connect
the cerebellum with other parts of
the brainstem
Instructions to motor neurons are
carried from the brain by
descending tracts
The corticospinal tracts arise in the
_______ and end in the____ (after crossing the midline).
Cerebral cortex, spinal cord
Why do both motor and sensory tracts decussate?
Each side of the brain controls the other side of the body
Degenerate corticospinal tracts are replaced by
Astrocytes
Corticospinal and rubrospinal tract similarities
Both tracts are dorsal to the denticulate ligament
- > voluntary movement
- > descending
Corticospinal and rubrospinal tract differences
- Rubrospinal tract synapses at red nucleus
- Rubrospinal has fewer axons
- Corticospinal tract modulates sensory info
The corticospinal tracts arise from
neurons in the cerebral cortex and pass down the brainstem near its ventral surface
Corticopontine fibres
information from cerebral cortex via pons to cerebellum
The basilar artery supplies
the pons
Locked in syndrome occurs when
a branch of the basilar artery supplying the
corticospinal tracts is blocked
In the open medulla what structure is noted
Olives
In a section of closed medulla we see
Central canal and pyramids
How do Primary afferent fibres in peripheral
nerves carry sensory information to the
spinal cord ?
Through dorsal root
Dorsal root ganglion contains cell bodies of
sensory neurons
1a fibre function
Monitors muscle stretch speed changes
C fibre function
pain
Abeta function
position
General pattern of somatosensory tracts
- Primary sensory neurones
- Second order neurones on same side of CNS
- > cross midline - Neurons in thalamus send signals to somatosensoy cortex
Two important somatosensory pathways in the spinal cord are? and their functions?
- Spinothalamic tract: nociception(pain); temperature; touch
- Dorsal column/ medial lemniscus system: two point discrimination; conscious prioprioception; vibration sense
Outline spinothalamic tract pathway
- Starts cerebral cortex
- Synapse in thalamus
- Axon in spinothalamic tract
- Synapse in superficial dorsal horn of SC
- Primary afferent to skin/muscle
Outline dorsal column/ medial lemniscus system pathway
- Starts cerebral cortex
- Synapse in thalamus
- Axon in medial lemniscus
- Synapse in medulla -> second order neuron in dorsal column nucleus
- Axon in dorsal column until large primary afferent in drg reaches skin
Lumbar cord gives rise to
lumbar spinal nerves mainly for lower limbs
c fibres (nociceptive) end in
the superficial dorsal horn
Second order neurons have axons that cross the midline to
join the spinothalamic tracts
Fasciculus gracilis carries information from what part of the body?
from the middle thoracic and lower limbs of the body
Where are the lower limb fibres in the medial lemniscus?
lateral mid-pons/ mid brain
Which structure in the midbrain has descending control over pain?
Periaqueductal grey
